Are You Confident of the Diagnosis?

What you should be alert for in the history

Dyshidrotic dermatitis or dyshidrotic eczema is characterized by small vesicles on the lateral aspects of the fingers and sometimes the soles of the feet. This condition was originally believed to be due to dysfunction of the sweat gland or “dyshidrosis,” but this concept has subsequently been disproved. It should be considered in the broader group of vesicular palmoplantar eczemas, which includes pompholyx, dyshidrotic eczema, hyperkeratotic hand dermatitis, and id reactions. The entities in this group can be difficult to distinguish from each other and from atopic and irritant and allergic contact dermatitis.

Patients with dyshidrotic dermatitis can typically describe a history of exacerbations characterized by vesiculation interspersed with asymptomatic periods. Some patients report prodromal sensory symptoms preceding the vesicular phase. As it becomes more chronic, the condition can be dominated by fissuring and hyperkeratosis.

Features that distinguish dyshidrotic hand dermatitis from other palmoplantar dermatitis are

--Pompholyx is a term best reserved for acute, explosive outbreaks of small to large vesicles and bullae on the palms and soles. Etiologic associations have been made between the spring and fall seasons and with stress. Some authors consider pompholyx to be a severe form of dyshidrotic dermatitis.

--Chronic hyperkeratotic hand dermatitis typically involves the central palms. Though vesicles do not dominate the clinical appearance of the lesions, histologic examination will demonstrate spongiosis that is indistinguishable from the other members of this group.

--An id reaction is a vesiculobullous dermatitis on the lateral aspect of the fingers. This dermatitis is elicited as a reaction to an infection in another part of the body, typically a fungal infection of the feet.

Characteristic findings on physical examination

During the acute, vesicular phase, dyshidrotic dermatitis will present as 1 to 2mm vesicles filled with clear fluid on the lateral aspects of the fingers, palms, and soles (Figure 1). Since this disease has a chronic and relapsing course, patients may have a bland physical examination at the time of their clinical presentation. Additionally, in the chronic stages, the areas can become fissured and hyperkeratotic, complicating the presentation and making it difficult to distinguish from other forms of hand dermatitis. Typically, the location on the lateral fingers and the relapsing course are strong clues to the diagnosis of dyshidrotic dermatitis (Figure 2).

Expected results of diagnostic studies

Histopathology: In the acute phase, histologic examination of the affected areas will demonstrate intraepidermal spongiosis and vesicle formation. A superficial perivascular infiltrate of lymphocytes can be present. In more chronic lesions the epidermis can show hyperkeratosis and even psoriasiform epidermal hyperplasia. Special stains (Periodic acid-Schiff) can be used to exclude the presence of fungi.

Serologic Testing: There are no specific laboratory abnormalities in dyshidrotic hand dermatitis.

Two of these entities, irritant and allergic contact dermatitis, deserve special mention. Irritant contact dermatitis is by far the most common etiology of hand dermatitis. It is often seen in the context of an occupation that involves “wet-work” and careful history can reveal a pattern of occupational exacerbation. Irritant hand dermatitis typically affects different parts of the hand than dyshidrotic dermatitis. Irritant contact dermatitis affects the dorsal fingertips as opposed to the lateral fingers and lateral palms, which are affected in dyshidrotic dermatitis.

Allergic contact dermatitis can be clinically indistinguishable from dyshidrotic dermatitis. Patch testing should be considered in patients with a recurrent dermatitis or atypical presentations. Some common allergens to consider in these patients include formaldehyde releasers, p-phenylenediamine, quaternium-15, fragrances, rubber, colophony, and lanolin.

Who is at Risk for Developing this Disease?

The prevalence of hand dermatitis varies by report and is thought to be between 2% to 8.9% of the general population. Irritant contact dermatitis is the most likely etiology of hand dermatitis. Dyshidrotic dermatitis may comprise about 20% to 25% of cases of hand dermatitis.

What is the Cause of the Disease?

Etiology

Pathophysiology

The etiology and pathogenesis of dyshidrotic dermatitis is, as of yet, unknown. In most patients a direct cause will not be identified.

Systemic Implications and Complications

Dyshidrotic dermatitis as an entity is not associated with any systemic complications. It has been reported to be more common in individuals with atopy.

Treatment Options

Optimal Therapeutic Approach for this Disease

Treatment options for dyshidrotic dermatitis are summarized in the Table 1.

Table I.

Treatment options for dishydrotic dermatitis

Topical Treatments

Physical Treatment Modalities

Systemic Treatments

High potency topical corticosteroids

Grenz ray

Prednisone

Drying agents

Phototherapy (UVA-1, PUVA, UVB)

Cyclosporine

Iontophoresis

Mycophenolate mofetil

Emollients

Intraepidermal botulinum toxin

Methotrexate

Topical Treatments

High potency topical corticosteroids are the first-line agents used in the treatment of dyshidrotic dermatitis. For the palms and soles, clobetasol ointment may be used up to twice daily. Their efficacy can be enhanced when used under occlusion with white, cotton gloves to limit the potential for sensitization.Topical drying agents can be used in the acute vesicular phases like ammonium lactate 12% or carmol 20% cream. Daily emollient therapy with petrolatum (Vaseline) can also prove to be quite useful for these patients, both in the acute phase and during the periods between exacerbations.

Physical Treatment Modalities

For patients who fail topical treatment, a physical treatment modality may be necessary to control their dyshidrotic dermatitis. Though only available in a few centers, superficial radiotherapy with the Grenz ray has been demonstrated to be successful in the treatment of dyshidrotic dermatitis in double-blind trials.

Phototherapy with psoralens and UVA (PUVA), UVB, or UVA-1 has been employed in the treatment of severe cases of dyshidrotic dermatitis. All three modalities have been utilized with good results. UVA-1 was shown to yield similar results to PUVA therapy and may be selected over PUVA due to its more favorable side effect profile.

Systemic Treatment Modalities

For patients with severe and refractory disease, systemic therapy may be necessary to control their dyshidrotic dermatitis. Oral prednisone can be of benefit, especially if treatment is initiated early in the acute phase. The authors almost never use systemic steroids except for full-blown pomphlyx, in which case we have started with 1mg/kg/day for 1 week and then reducing the dose by half every week for 3 to 4 weeks. Cyclosporine, mycophenolate mofetil, and methotrexate have all been shown to improve dyshidrotic dermatitis; however, their use is limited by potential side effects and should be reserved for the most severe cases; the doses are similar to those used for the treatment of severe psoriasis or atopic dermatitis.

We have used oral acitretin with mixed success.

Patient Management

Patients should be educated about the relapsing nature of this disease and encouraged to keep track of potential triggers, so that they might be avoided. Most patients can be managed with topical treatments using a two-step approach: high potency topical steroids during the acute phase and emollient use at all times.

Unusual Clinical Scenarios to Consider in Patient Management

Since there is considerable overlap between all types of hand dermatitis, patients who fail to improve with first-line therapy should be carefully evaluated. In these patients the clinician should consider the possibility that an irritant or allergic contact dermatitis is either the primary process or contributing to the dyshidrotic dermatitis. If an allergic contact dermatitis is suspected, patch testing can be invaluable. For patients with an irritant contact dermatitis, avoiding exacerbating exposures and protective equipment (vinyl gloves) can be useful.

(In the evaluation of a patient with hand dermatitis a careful link between occupational exposures and symptoms should be evaluated. In some cases the hand dermatitis can be due to an allergic contact dermatitis, and patch testing can demonstrate the culprit allergen.)